Fig. 2: Photograph and characterizations of the carbon nanotube (CNT) field emission X-ray source array.

a The photograph of the CNT field emission X-ray source array with the external multisource collimator. b The radiation fields formed by the eight collimated beams were recorded at 200 mm away from the focal line using a flat panel detector. c The X-ray dose rate profiles were measured at the detector surface using a dose meter (Raysafe X2, Unfors Raysafe AB, Sweden), with the source operating at 90 kVp, 15 mA anode current and 6.5 ms exposure per source with 0.3 mm Cu filtration.